Problem: What is the midline equation of the function $h(x)=-4\cos(5x-9)-7$ ? $ y=$
Explanation: Midline in sinusoids of the form $f(x)=a\cos(bx+c)+d$ Graphically, the midline of a sinusoidal function is the horizontal line that passes exactly in the middle of its extreme values. The midline equation of a sinusoid of the form $f(x)={a}\cos(bx + c) + {d}$ is equal to $y={d}$. [How can we justify this given our graphical understanding of midline?] Finding the midline The midline equation of $h(x) = -4\cos(5x-9){-7}$ is $y={-7}$.